Dr. Xavier Fitch is a human character from the 1995 movie Species. He led that project to create Sil and later tries to kill her. Despite Sil being the main antagonist of the film, her amorality and lack of understanding makes her less villainous. Dr. Fitch, on the other hand, makes many conscious decisions that endanger humanity. All in all, Dr. Fitch is the true main antagonist of the film.
Dr. Fitch led several experiments that combined an alien DNA sequence with human ovums. He was successful in creating Sil, but, upon seeing her rapid aging and violent behavior in her sleep, decided to terminate the project and kill her. Upon her escape, Dr. Fitch compiled a team (consisting of Preston Lennox, Dr. Laura Baker, Dan Smithson, and Dr. Stephen Arden) to track her down.
Dr. Fitch and his team pursue Sil across L.A., following various sightings and murder reports. They nearly catch her before she fakes her own death by crashing a car. Believing they have succeeded in their mission, the group heads back to their hotel where Dr. Arden sleeps with, impregnates and is killed by Sil. Dr. Fitch and the remaining team cashes Sil into the sewer. Dr. Fitch is killed during the search by Sil.
Dr. Fitch is self-serving and a jerk. He is the individual who initially created Sil, without bothering to test the alien DNA to see if it was dangerous and think about the possible consequences of creating a whole new life form. Fitch is shown mistreating and even putting his team's lives at risk. During their final search for Sil in the sewers, Fitch verbally abuses Dan, who is a psychic, when the later can not detect Sil. Part way through their pursuit of Sil, the team finally decides to test the alien DNA by itself; due to equipment malfunctions, Laura and Preston go into the test chamber with the newly forming alien specimen. The specimen grows at a rapid rate; the containment container the specimen is in cannot be closed due to a bolt being lost. Despite there being plenty of time for Laura and Preston to leave, Fitch refuses to let them out of the test chamber. Only when there is a few seconds before the test chamber is lit on fire does Dr. Arden let them out.